Many organic materials, especially polymers and polymeric films, display a decided tendency to acquire an electrostatic charge when handled or processed. This results in a number of known practical difficulties, for example, in manufacturing operations and subsequent uses. The prior art has dealt with the control of static charges by bleeding them off using conductive materials as antistatic agents. Varying degrees of success have been obtained with inorganic metallic foils, vacuum metallizing, and conductive coatings on polymeric substrates.
Polymers having antistatic properties have been prepared by free-radical or cationic polymerization of certain vinyl monomers. U.S. Pat. No. 4,248,750 relates to a linear siloxane with pendant vinyl groups that crosslinks by hydrosilation to provide a polymer having both silane-type and carbon-type linkages in its backbone. W. German Offenlegungsschrift No. 2,051,832 discloses a vinyl monomer copolymerized with a silanol-containing vinyl monomer, hydrolyzed with sulfuric acid, and then cured to produce an antistatic polymer having a large proportion of carbon to carbon linkages in its backbone.
Also known in the art are polymers having antistatic properties which have been prepared by polymerization through a silicon functionality. In U.S. Pat. No. 4,294,950 monomers having silane and epoxide functionality are subjected to hydrolysis of the silane moieties to provide silanols. Polymerization and curing in the presence of polyvalent carboxylic acids and curing agents provide polymers having backbone polyester and siloxane groups.
Antistatic prior art materials frequently suffer from a serious performance deficiency; namely, a critical dependence of conductivity on relative humidity. Prior art materials, other than metal-like conductors, provide little, if any, static protection below 20 percent relative humidity. Many such materials impart a greasy feel to the article and the antistatic performance can be adversely affected by washing with solvents. These materials frequently exhibit inadequate abrasion resistance, durability, and transparency. There remains a need in the art for polymeric materials having antistatic properties at very low relative humidities.
Dilute aqueous solutions of certain terminal monohydroxy-substituted organosilanols have been disclosed in U.S. Pat. No. 3,161,611 as useful for impregnation of paper, textiles, leather and other materials. Coating compositions comprising these silanols are not described. Aqueous di- or polyhydroxy-substituted organosilanols, with or without silanol-sulfonate compounds, are novel in the art. The cured coated compositions of any of the above materials have not been previously disclosed.